1/*
2 * Copyright (C) 2011, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1.  Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2.  Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#ifndef WaveShaperDSPKernel_h
26#define WaveShaperDSPKernel_h
27
28#include "platform/audio/AudioArray.h"
29#include "platform/audio/AudioDSPKernel.h"
30#include "platform/audio/DownSampler.h"
31#include "platform/audio/UpSampler.h"
32#include "modules/webaudio/WaveShaperProcessor.h"
33#include "wtf/OwnPtr.h"
34
35namespace blink {
36
37class WaveShaperProcessor;
38
39// WaveShaperDSPKernel is an AudioDSPKernel and is responsible for non-linear distortion on one channel.
40
41class WaveShaperDSPKernel FINAL : public AudioDSPKernel {
42public:
43    explicit WaveShaperDSPKernel(WaveShaperProcessor*);
44
45    // AudioDSPKernel
46    virtual void process(const float* source, float* dest, size_t framesToProcess) OVERRIDE;
47    virtual void reset() OVERRIDE;
48    virtual double tailTime() const OVERRIDE { return 0; }
49    virtual double latencyTime() const OVERRIDE;
50
51    // Oversampling requires more resources, so let's only allocate them if needed.
52    void lazyInitializeOversampling();
53
54protected:
55    // Apply the shaping curve.
56    void processCurve(const float* source, float* dest, size_t framesToProcess);
57
58    // Use up-sampling, process at the higher sample-rate, then down-sample.
59    void processCurve2x(const float* source, float* dest, size_t framesToProcess);
60    void processCurve4x(const float* source, float* dest, size_t framesToProcess);
61
62    WaveShaperProcessor* waveShaperProcessor() { return static_cast<WaveShaperProcessor*>(processor()); }
63
64    // Oversampling.
65    OwnPtr<AudioFloatArray> m_tempBuffer;
66    OwnPtr<AudioFloatArray> m_tempBuffer2;
67    OwnPtr<UpSampler> m_upSampler;
68    OwnPtr<DownSampler> m_downSampler;
69    OwnPtr<UpSampler> m_upSampler2;
70    OwnPtr<DownSampler> m_downSampler2;
71};
72
73} // namespace blink
74
75#endif // WaveShaperDSPKernel_h
76